求翻译：在高等数学的解题中，有些题目，比如极限，二重积分、不定积分与定积分的计算中，若使用了换元法，就会化难为易，化繁为简，节省计算，在考试中节省大量的时间。本！是什么意思？

In higher mathematics, problem solving, some topics, such as the limit, the double integral, indefinite integral and definite integral calculation, if using the substitution method will be of Aesthetic, to simplify, save calculation in the examination save a lot of time. This!

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In the higher mathematics problem solving, some topics, for instance the limit, the double integral, the indefinite period dispense the definite integral in the computation, if has used the substitution of variables, can melt thanks easily, simplifies, saves the computation, saves the massive time i

In higher mathematics in solving problems, some of the topics, such as limit, double integral, indefinite integral and definite integral calculation, conversion method are used, it will turn hard on easy, to simplify, save calculations, saving a lot of time in the exam. The present!